In a sometimes feisty clash with MLAs, he defended the £1.3bn disposal, claiming it had been a good deal for Northern Ireland.

He added the probe was an example of the Assembly taking gold and turning it into muck.

The committee is examining allegations surrounding the sale of Nama's Northern Ireland assets in April 2014.

The 850-property portfolio - known as Project Eagle - was sold to Cerberus Capital Management, a US investment firm.

But the deal is now under investigation by the National Crime Agency after explosive allegations made in the Dail by Mick Wallace.

The independent TD alleged that £7m was due to be paid to a Northern Ireland politician following the sale.

Mr Wilson, who was Finance Minister between July 2009 and July 2013, yesterday strongly defended the deal.

"Although I didn't see the end product, overall I believe that what we got from Nama - contrary to the views which have been expressed by some members of this committee - was actually a very good deal," he said.

Mr Wilson added: "This Assembly has been very good at finding gold and turning it into muck, and I think that is what has happened to a certain extent with the way that this committee has handled some of the subsequent events."

He proceeded to accuse the committee of "incompetence and bias" in how it dealt with the inquiry.

Mr Wilson also claimed that MLAs had taken allegations with no fact or substance from people who were "useful idiots" - an apparent reference to Jamie Bryson.

Mr Bryson previously told the committee that First Minister Peter Robinson was among five people to receive a share of a "success fee" linked to the Nama sale.

Mr Robinson strongly denies Mr Bryson's allegations.

"There is an important job that this committee should have been doing all along, and that is separating out fiction and prejudice from actual fact," Mr Wilson added.

Later he clashed with Mairtin O Muilleoir over the Sinn Fein MLA's reference in previous hearings to Belfast businessman Gareth Graham.

Mr Graham has previously raised concerns over Nama's activities.

Mr Wilson said Mr Graham was a regular advertiser in the Andersonstown News and North Belfast News, part of the Belfast Media Group, of which Mr O Muilleoir is a director.

He told Mr O Muilleoir: "Almost every week you have raised the issue of Mr Gareth Graham, either directly or indirectly.

"Now Mr Gareth Graham obviously pays your company quite a lot of money. In fact, every week in the Andersonstown News and the North Belfast News he takes two-page advertisements, which I'm sure cost a pretty penny."

Mr Wilson questioned whether Mr O Muilleoir had declared this to the committee.

He said Standards Commissioner Douglas Bain may be interested in the matter.